linux-php Slow log always has + + + Dump failed error

PHP Slow log always have + + + Dump failed error, online search for a lap did not find the answer, hope to get everyone's guidance.

The detailed log is as follows:
[17-dec-2015 16:28:30] [Pool www] pid 29220
Script_filename =/var/tt/mm.php
[0x00000000023b6990] curl_exec ()/var/tt/my.php:20
[0x00000000023b5088] Http_request_json ()/var/tt/mm/login.php:75
[0X00000000023B4A20] + + + dump failed

[17-dec-2015 16:29:54] [Pool www] pid 29544
Script_filename =/var/tt/mm_reg.php
[0x00000000022231c0] curl_exec ()/var/tt/my.php:20
[0x0000000002220ae0] Http_request_json ()/var/tt/mm_reg.php:235

[17-dec-2015 16:36:19] [Pool www] pid 20815
Script_filename =/var/tt/mm_reg.php
[0x00000000023b7160] curl_exec ()/var/tt/my.php:20
[0X00000000023B4A80] Http_request_json ()/var/tt/mm_reg.php:235

[17-dec-2015 16:48:46] [Pool www] pid 27734
Script_filename =/var/tt/mm.php
[0x00000000023b69f0] curl_exec ()/var/tt/my.php:20
[0x00000000023b50e8] Http_request_json ()/var/tt/mm/login.php:75
[0X00000000023B4A80] + + + dump failed

[17-dec-2015 17:02:26] [Pool www] pid 3215
Script_filename =/var/tt/mm_reg.php
[0x0000000002370800] curl_exec ()/var/tt/my.php:20
[0x000000000236e120] Http_request_json ()/var/tt/mm_reg.php:235

[17-dec-2015 17:08:39] [Pool www] pid 5503
Script_filename =/var/tt/mm.php
[0x00000000023a87a0] curl_exec ()/var/tt/my.php:20
[0x00000000023a6e98] Http_request_json ()/var/tt/mm/login.php:75
[0x00000000023a6830] + + + dump failed

[17-dec-2015 17:12:04] [Pool www] pid 6592
Script_filename =/var/tt/mm.php
[0x00000000023b69f0] curl_exec ()/var/tt/my.php:20
[0x00000000023b50e8] Http_request_json ()/var/tt/mm/login.php:75
[0X00000000023B4A80] + + + dump failed

[17-dec-2015 17:31:51] [Pool www] pid 19806
Script_filename =/var/tt/mm_reg.php
[0x00000000023707d0] curl_exec ()/var/tt/my.php:20
[0x000000000236e0f0] Http_request_json ()/var/tt/mm_reg.php:235
[Root@iz286xgh6itz log]# + + + dump failed

Reply content:

PHP Slow log always have + + + Dump failed error, online search for a lap did not find the answer, hope to get everyone's guidance.

The detailed log is as follows:
[17-dec-2015 16:28:30] [Pool www] pid 29220
Script_filename =/var/tt/mm.php
[0x00000000023b6990] curl_exec ()/var/tt/my.php:20
[0x00000000023b5088] Http_request_json ()/var/tt/mm/login.php:75
[0X00000000023B4A20] + + + dump failed

[17-dec-2015 16:29:54] [Pool www] pid 29544
Script_filename =/var/tt/mm_reg.php
[0x00000000022231c0] curl_exec ()/var/tt/my.php:20
[0x0000000002220ae0] Http_request_json ()/var/tt/mm_reg.php:235

[17-dec-2015 16:36:19] [Pool www] pid 20815
Script_filename =/var/tt/mm_reg.php
[0x00000000023b7160] curl_exec ()/var/tt/my.php:20
[0X00000000023B4A80] Http_request_json ()/var/tt/mm_reg.php:235

[17-dec-2015 16:48:46] [Pool www] pid 27734
Script_filename =/var/tt/mm.php
[0x00000000023b69f0] curl_exec ()/var/tt/my.php:20
[0x00000000023b50e8] Http_request_json ()/var/tt/mm/login.php:75
[0X00000000023B4A80] + + + dump failed

[17-dec-2015 17:02:26] [Pool www] pid 3215
Script_filename =/var/tt/mm_reg.php
[0x0000000002370800] curl_exec ()/var/tt/my.php:20
[0x000000000236e120] Http_request_json ()/var/tt/mm_reg.php:235

[17-dec-2015 17:08:39] [Pool www] pid 5503
Script_filename =/var/tt/mm.php
[0x00000000023a87a0] curl_exec ()/var/tt/my.php:20
[0x00000000023a6e98] Http_request_json ()/var/tt/mm/login.php:75
[0x00000000023a6830] + + + dump failed

[17-dec-2015 17:12:04] [Pool www] pid 6592
Script_filename =/var/tt/mm.php
[0x00000000023b69f0] curl_exec ()/var/tt/my.php:20
[0x00000000023b50e8] Http_request_json ()/var/tt/mm/login.php:75
[0X00000000023B4A80] + + + dump failed

[17-dec-2015 17:31:51] [Pool www] pid 19806
Script_filename =/var/tt/mm_reg.php
[0x00000000023707d0] curl_exec ()/var/tt/my.php:20
[0x000000000236e0f0] Http_request_json ()/var/tt/mm_reg.php:235
[Root@iz286xgh6itz log]# + + + dump failed

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